Welcome to the North American Subaru Impreza Owners Club Sunday November 23, 2014
Home Forums WikiNASIOC Products Store Modifications Upgrade Garage
NASIOC
Here you can view your subscribed threads, work with private messages and edit your profile and preferences Home Registration is free! Visit the NASIOC Store NASIOC Rules Search Find other members Frequently Asked Questions Calendar Archive NASIOC Upgrade Garage Logout
Go Back   NASIOC > NASIOC Technical > Factory 2.0L Turbo Powertrain (EJ Series Factory 2.0L Turbo)

Welcome to NASIOC - The world's largest online community for Subaru enthusiasts!
Welcome to the NASIOC.com Subaru forum.

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, free of charge, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, so please join our community today!

If you have any problems with the registration process or your account login, please contact us.
* Registered users of the site do not see these ads.
Reply
 
Thread Tools Display Modes
Old 07-05-2001, 12:48 AM   #1
thng
Scooby Specialist
 
Member#: 8062
Join Date: Jul 2001
Location: Moreno Valley, CA
Vehicle:
2002 WRX
Silver

Default Boost curve

I read the posting on the 15 psi pressure readings. Though I haven't taken any measurements myself, I am curious as to whether the pressure level is steady at the point that the maximum pressure is achieved, at what rpm does this pressure level arrive, and what is the pressure level at 7Krpm?

I know I encountered a rev limiter somewhere at about 7.5Krpm. I am trying to determine why there appears to be degredation of performance (or lack of increased performance) above, say, 5Krpm?

I realize that the cats, as well as the rest of the system, in the exhaust contribute to this so I disconnected the exhaust system after the last O2 sensor and ran again. There was not much imrpovement in the area above 5Krpm but a noticeable improvement where the boost curve is normally on the rise (3.5K to 4.5K rpm).

I plan to make changes but would like to gather some information before I start doing something I might regret later.
* Registered users of the site do not see these ads.
thng is offline   Reply With Quote
Old 07-05-2001, 12:59 AM   #2
RidinLow
Scooby Guru
 
Member#: 329
Join Date: Sep 1999
Chapter/Region: Tri-State
Location: NJ
Vehicle:
1995 325i
Arctic Gray

Default

Boost trails off to around 12-13 psi around redline because the stock turbo isn't big enough to flow that much air at high rpms. It's literally running out of breath, which is the price you pay for lower end response.
RidinLow is offline   Reply With Quote
Old 07-05-2001, 03:25 AM   #3
thng
Scooby Specialist
 
Member#: 8062
Join Date: Jul 2001
Location: Moreno Valley, CA
Vehicle:
2002 WRX
Silver

Default

Thank you for that information. I thought this would have been the likely conclusion.

Now then, I am contemplating a modfication to the turbo to install a larger compressor wheel. This over replacing the turbo outright with something that would require quite a bit of modification to other parts of the exhaust.

Would you know or have any idea what the back pressure is at the high rpm? I ask because I know that MRT Performance sells a turbo header system for the WRX. The pictures on their website present a very good looking system at AU$1000+.00

Also, I don't think anyone likes that convoluted turbo inlet pipe that routes itself underneath the manifold. Has anyone ever attempted to redesign that particular part?

Finally, I know from my GTP days, that we ran without a blow off valve and had the compressor wheel pinned to the shaft to prevent the wheel from backing off. Removing the blow off valve in a stock application increases the likelihood of the compressor wheel backing off if the nut is a standard locking nut. What about the intercooler? In short, in terms of overall system pressure, what is a stock system capable of withstanding?

Is a stock system (block, internals, etc) capable of withstanding regular bursts of, perhaps, 400bhp regardless of how that power is achieved? I was, originally, contemplating the use of a NOS system but thought better of it because I could not accept drilling and tapping in weird places of the manifold.

Finally, the earlier subarus (from my own research) were notorious for having weak 1st and 2nd gear sets. How does the new WRX stand in this regard? I don't plan any kind of drag racing but I'd still like to know.
thng is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
boost curve and timing curve questions C J Factory 2.5L Turbo Powertrain (EJ Series Factory 2.5L Turbo) 9 08-24-2007 04:03 PM
Stock Boost curve mightbewrx Factory 2.0L Turbo Powertrain (EJ Series Factory 2.0L Turbo) 1 08-13-2002 10:00 PM
Boost Curve Subi-fied Factory 2.0L Turbo Powertrain (EJ Series Factory 2.0L Turbo) 9 06-06-2002 12:31 PM
2002 WRX Boost Curve - is this right? Edward Jay Factory 2.0L Turbo Powertrain (EJ Series Factory 2.0L Turbo) 16 05-17-2001 07:22 AM


All times are GMT -4. The time now is 05:43 AM.


Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2014 Axivo Inc.
Copyright ©1999 - 2014, North American Subaru Impreza Owners Club, Inc.